This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Type 1 diabetes (T1D) is a disease that results from the destruction of pancreatic [unreadable]??-cells. The incidence is highest in children and adolescents. Although all people are susceptible, relatives of individuals with T1D are at much greater risk for development of the disease. Genetic factors contribute to most cases of T1D. Associated human leukocyte antigens (HLA,the immune response by white blood cells) have been found to be strongly predictive of T1D. Environmental factors also appear to contribute to the disorder. Epidemiological studies have suggested that other factors such as viral infections may be involved in the origin and development of T1D. Despite many improvements in the last two decades, current therapy for T1D remains unsatisfactory. Treatment for most individuals begins after the onset of symptomatic hyperglycemia. Strategies attempt to restore normal glycemia through insulin injections and changes in daily activities. The goals of the TrialNet Natural History Study of the Development of T1D are to gain information about the pathogenesis and natural history of T1D and to facilitate the recruitment and assessment of individuals who might qualify for T1D prevention trials. The information obtained from this study will serve to enable the development and implementation of prevention trials.